Screw lamp extractor and replacer including broken lamp cap extractor



Oct. 28, 1947. IE. I EvlcaHA SCREW LAMP EXTRACTOR ANDv REPIJACEl INCLUDING BROKEN LAMP CAP EXTRACTOR Filed July 19, 1945 r l 25 f; l ql@ l 'I 'fj Z5 '14 121 27 C l', l4

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vSCREW LAMP EXTRACTOR AND REPLAGER INCLUDING BROKEN LAMP CAP EXTRACTOR Filed'July 19, 1945 2 Sheets-Sheet 2 ,9 ai Y Patented Oct. 28, l1947 SCREW LAMP EXTRACTOR AND REPLACER INCLUDING BROKEN LAlWP CAP EX- TRACTOR Edward Leigh, Speke, Liverpool, England Application July 19, 1945, Serial No. 605,897 In Great Britain June 6, 1944 2 Claims. (Cl. 294-20) The invention relates to a screw lamp replacer and extractor. In such places as machine shops and .printing shops, an electric screw lamp, out of reach from the floor', which has burned out or which has been destroyed or damaged while in its socket, cannot be safely removed by hand during the operation of adjacent machines. As good lighting is often imperative for the operative control of such machinery, this means that all adjacent machinery must be brought to a standstill while ladders or other makeshift and often dangerous erections are transported and set up to enable a useless lamp to be reached and replaced. 'Such erections have then to be removed or dismantled before the machinery can be safely restarted.

, These and other disadvantages apply also in such places as operating theatres and buildings in which the general public assembles. A further 'diculty arises inthe case of a lamp which has been accidentally broken in its socket since the remains of the jagged glass bulb are liable to cause injury to the person attempting to unscrew the broken glass and cap from the lamp socket.

Another undesirable consequence of previous lamp removal methods is that in order to minimize the standstill of adjacent machinery, the electric power may be kept on in the mains during the removal of a single broken lamp. This endangers the person effecting the removal or replacement of the lamp, since by accidentally connecting with the exposed lamp laments, the charge from the mains may nd a path through the body of such person and cause a severe shock.

These and other serious disadvantages hitherto, inherent in lamp removing and replacing are overcome by the present invention which comprises a screw lamp replacer and extractor of the type having a base, at least two lamp gripping members hinged to the base and returned by spring means, support means connected to the base and exible means in connection with the gripping members to move the latter towards each other against the action of the spring returning means and including control means for the flexible means comprising a collar adjustably secured to the support means, a projecting member connected to the collar and forming a curved rack, a handle pivoted to the projecting member and engageable with the curved rack, said handle being connected with the flexible means to operate the latter.

In the preferred embodiment, the control means includes automatic means to prevent pivoting ofthe handle in a direction to permit opening of said gripping members, said means comprising a pawl on the handle engageable with the curved rack to prevent pivoting of the handle in said direction, and spring meansA on the handle to urge the pawl into engagement with the curved rack.

Means is also provided on the control means to counteract the automatic means, including a trigger on the pawl operable when moved against the action of the spring means on the handle to release the pawl from engagement withl the curved rack to permit pivoting of the handle in either direction and thus enable the gripping members to be adjusted to engage lamp bulbs of dilTerent sizes. The invention also .comprises a screw lamp replacer, wherein the gripping members are slotted and detachable lamp extractor means is in-v eluded, said means comprising a base having slots: therein corresponding to those of the gripping members, said base being mountable by said slots to form an assembly with the gripping members, a shank projecting upwardly from said base and having a dielectric portion intermediate its ends, and fin like members, each having a curved knife edge terminating in a common apex at the upper end of the shank and adapted when inserted into a broken lamp cap to engage and unscrew the latter when the said assembly is rotated in an unscrewing direction.

The invention will now be described with ref erence to the accompanying drawings in which:

Figure 1 is a partly sectional elevation of the device.

Figure 2 is an enlarged plan View of the control device shown in the lower part of Figure 1.

Figure 3 is a plan of the device.

Figure 4 is a plan of the broken lamp cap extractor.

Figure 5 is an elevation of Figure 4, and

Figure 6 is a detail of one form of gripping member.

The device comprises a triangular base I0 having upturned corners I I forming supports for the ange members l2, Secured to members l2 by pivots I3 are the crank arms I4, arranged so that their upper ends are pivotable towards and away from a common point A (Figure 3). The pivoted crank arms are normally held in open position, with their upper ends separated, by means of the springs l5 interconnecting the base portions I 5 of adjacent members I4.

The triangular member l0 includes an internally threaded projecting member I1 secured thereto, preferably by Welding, into which is secured the tubular supporting member I8 of any desired length. To the innermost portion I6 of each gripping member is secured a link member 20. The links are connected at their lower ends to a common tension spring 2I disposed inside member I8. To the lower portion of spring 2| is secured a flexible member 22, passing down the tube I8 and out of the latter through an oririce 23 adjacent to the control means generally represented by the numeral 24.

For engagement with electric light bulbs of different contours, the gripping members I4 are provided with horizontally aligned detachable bulb grips 25 and 26 disposed adjacent to the inner edges of members I4. An annular supporting member 21 is detachably secured to the inner edge of one gripping member to form a support for round-surfaced bulbs. Members 25, 26 and 21 are preferably provided with padded surfaces so as to prevent damage to the glass of the bulb during extracting or replacement.

It will be understood that bulb support members such as 25, 25 and 21 having various curvatures and shapes may be secured to the gripping members so that the latter can securely grip a screw bulb of any contour, as required. For example, these may take the form illustrated at 28 in Figure 6, being pivotally secured as at 29 to members I4. Also, since the gripping members I4 are easily .detachable from the pivots I3, gripping members having other shapes than those illustrated may be employed to deal with particular bulbs.

By reference to Figures 1 and 2 it will be seen that a control means 24 for the flexible means is disposed below the orifice 23. This means comprises a member in the form of a split collar 35, detachably secured to the tubular supporting member I8 by the screws SI through projections 32 and 33 on the collar. Projecting from the split collar and xedly secured between the members 32 and 33, is a semicircular projecting member 34 having ratchet teeth 35 disposed around its periphery. Pivoted to the member 24 as at 36 is a handle formed of adjacent arms 31 each disposed on one side of the semicircular member 34. The arms 31 are spaced from each other by the `member 3%! secured to them by rivets 39, thus forming a convenient pivoted and recessed handle 41.

Adjacent to the toothed edge of member 34 and disposed in the recess i9 between the arms 31, is a pawl 4B pivoted on a member 44 secured through arms 31. The pawl has a portion 45 which is shaped to correspond with the teeth 33 and an extended rear portion 42 formed as a trigger. 'I'he pivot member 44 projects laterally of one arm 31 to form a boss 45 to which the lower end of the flexible member 22 is secured. Adjacent to the pawl in recess I9 is a spring 43 disposed to bear against the rear portion 42 of the p-awl. The tension of the spring is arranged to urge the portion i5 of the pawl into engagement with theteeth 35 and automatically prevent upward movement of the handle when the spring is not counteracted by pressure on the trigger.

It will be understood that the purchase of the gripping members on a bulb of given size depends on the proper tensioning of member 22 in relation to the movement of handle 41. This is controlled by the location of the collar member 3U. For any given bulb the tensioning may be correctly adjusted by rst slackening the members 3l to loosen the collar relative to member I8. The member 41 is then depressed until the pawl on the latter is engaged in one of the lower teeth of the ratchet as at 35a and, simultaneously, the grips 26 are in contact with each other. Member 35 is tightened on to member I8, and is then properly positioned in combination with its flexible member 22 so as to make full use of the range of movement of member 41.

The operation of the lamp-extracting and replacing part of the device, thus far described, is as follows. Assuming, that it is required to remove a damaged lamp, the device is positioned by means of the supporting member or mast I8 so that the bulb is approximately centered between the members I4 and preferably with the bulb base resting in the padded ring 21. By depressing the pivoted member 41, the lower ends I6 of members I4 are drawn downwardly. By means of pivots I3, disposed intermediate the ends of members I4, this results in .the grips 25 and 26 on the upper portions of members I4, being drawn drawn towards the common point A so that eventually they make contact with the bulb surface. When this occurs, through operation of the spring-urged pawl 4U, the purchase of the grips on the bulb will be maintained automatically. The device may then be rotated in an unscrewing direction while maintaining grip on the bulb which is thus removed from the socket and lowered .to the ground without breaking away from the gripping means. It will be evident that new bulbs may be inserted into sockets by reversing the procedure described.

Figures 4 and 5 illustrate the broken lamp cap remover. This comprises a triangular base having truncated corners as at 5I. Normal to each truncating edge and radial to the centre of the base are slots 52 each adapted to engage a substantially horizontal corresponding slot 53 in the upper inner edge of each member I4.

In the centre of the upper surface of the base 55 is a socket 54 into which is secured a shank member 55 made of dielectric material such as a suitable plastic. To the upper portion 55 of the shank member is secured a corresponding socket member 51. The latter is formed with radial slots 58, into which are inserted and secured fin like members 59. These are symmetrically arranged about the axis o-f the socket and shank. The n like members 59 are each provided with a curved knife edge 5I. All such edges preferably terminate in a common apex 60 substantially aligned with the axis of the shank.

In use, the cap extractor is mounted in connection with the gripping members by engaging the corresponding slots 52 and 53. The control member 41 is adjusted so that the gripping members exert suicient purchase on the slots 52 of member 56) to form a stable extractor assembly, in which the member 50 is substantially parallel to the member I0. It is to be noted that the slots 53 are positioned in relation to the shank member 55 so that when the extractor assembly is formed as described, the apex 5!) will project well beyond the uppermost portions of members I4. It will be evident that by operation of the spring-urged pawl, the tension of the resilient member 22 is automatically vmaintained so that the purchase of members i4 on the base 50 is sufficient to maintain the extractor assembly rigid when rotated.

To remove `a broken lamp cap, the apex 60 of the rigid assembly is inserted into the cap. The assembly is then rotated in an unscrewing direction according to the thread of the cap in its socket. Y

k The knife-edges 6I make contact with the nner portions of the cap which may thus be safely withdrawn from its socket. It will be appreciated that on account of the dielectric portion 55 of the shank, the n like members and upper socket 54 are insulated from al1 other portions of the apparatus which may thus be safely used regardless of whether the electrical connections of the broken cap are live or not. It will be evident that by means of the apparatus any type of bulb whether broken or otherwise can easily and safely -be removed or replaced from distances up to forty to fty feet.

What I claim is:

1. A screw lamp extractor and replacer cornprising a base, support means'connected to the base, at least three lamp-gripping members hingedly connected to the base intermediate their ends, a horizontal tension spring tending to move 6 corresponding slots provided in the lamp -grippin-g members, said base being montable by said slots to form an assembly with the gripping members, a shank projecting upwardly from said base and having a dielectric portion intermediate its ends, and fin like members, each having a curved knife edge terminating in a common apex at the upper end of the shank and adapted when inserted into a broken lamp cap to engage and unscrew the latter when the said assembly is rotated in an unscrewing direction.

EDWARD LEIGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES'PATENTS Number Name Date 543,814 Rohder et al July 30, 1895 693,200 Wilkin Feb. 11, 1902 923,376 Savage June 1, 1909 949,419 Edgerton Feb. 15, 1910 1,288,873 Grinnell Dec. 24, 1918 1,319,028 Grinnell Oct. 14, 1919 FOREIGN PATENTS Number Country Date Great Britain Mar. 19, 1897 

